"Consumer food marketing can be extremely persuasive, and the right buzzword on a package can lure a shopper into making an unwise purchase," Kari Kooi, a registered dietitian at the Methodist Hospital in Houston, said in a hospital news release. "We need to educate consumers on how to read nutrition labels so they can avoid falling prey to the 'health halo' effect."

Studies have shown that this "health halo" effect leads some people to eat twice as much or more of these foods because they are marketed as healthy, she says.

Five foods Kooi recommends avoiding are:

Vegetable chips. These are marketed as healthy substitutes for vegetables but the nutrition labels on most brands read the same as potato chips. Many of the vegetables' nutrients are lost in the processing of these chips. Choose real vegetables instead.

Nutrient-enhanced waters. Most are nothing more than colored sugar water that contain empty calories that contribute to weight gain. Claims that some of these products are a healthy choice because of added vitamins are just marketing hype, Kooi said. Taking a daily multivitamin with a glass of water is a better option, she said.

Muffins. If they're sprinkled with a few oats or packed with blueberries, consumers think they're a healthier choice than donuts. But muffins are really nothing more than cupcakes without icing, said Kooi. She also noted that mega-size muffins sold in coffee shops can contain 500 to 600 calories.

Premade smoothies. Most commercial ready-made smoothies are loaded with sugar and calories. You're better off making your own smoothies with high-quality, nourishing ingredients such as low-fat Greek yogurt, skim milk and fresh or frozen fruits, Kooi says.

Frozen yogurt. Although made with low-fat or fat-free dairy ingredients, frozen yogurt typically contains high amounts of added sugar. Many of the live and active cultures added to frozen yogurt cannot survive freezing, so you won't get any probiotic benefits, Kooi said. Probiotics help maintain the balance between good and bacteria in the digestive tract.

More information
The U.S. Centers for Disease Control and Prevention has more about nutrition.